15 years , Never had a cel (wtf)

[dakmon]

In the 15 years that I have had my Tsi, I have never had the cel come on except at start up. I have had my share of problems and am currently stumped by a low idle when warm accompanied by regular stalling issues.
Steve, or anyone else, what would cause my ecu to not throw a cel in that time span. I removed the board and it appears to be fine. Datalogger reads no errors.

Thanks

 

[steve]

The fact that it's never throw a CEL since new doesn't mean anything. Stuff gets old and capacitors go bad. Just because you can't see anything doesn't mean there isn't anything wrong. I see plenty of ECUs where the conformal coating sealed the electrolyte leakage under the cap and it was busy eating the circuit board but you wouldn't know it.
C106 has a ISC trace sitting directly under the capacitor. Guess what happens when that breaks? Poor idle and stalling problems depending on where your ISC got stuck.

Most of the ECU's I work on don't throw CEL's either.

Steve